JP6205674B2 - Method for producing fine fiber - Google Patents

Description

  The present invention relates to a method for producing fine fibers, and more particularly, to a method for producing fine fibers that can produce fine fibers more safely and easily and has improved productivity.

  Conventionally, fiber assemblies such as non-woven fabrics have been widely used as filter media, and the fiber diameter is appropriately set according to the object to be filtered. Specifically, the object to be filtered varies from a relatively large object such as dust contained in the air to a minute object of about 0.1 μm to 1 μm.

  It is known that fine fibers having a fine fiber diameter used for filtering such fine objects are produced by various production methods, for example, a needle-like nozzle to which a high voltage is applied. When the polymer solution is supplied to the polymer solution, electric charge is charged to the polymer solution that flows out linearly from this needle-shaped nozzle, and the distance between the charged charges decreases as the solvent of the polymer solution evaporates. When the Coulomb force increases and the Coulomb force exceeds the surface tension of the linear polymer solution, a phenomenon occurs in which the linear polymer solution is stretched explosively, and this phenomenon is primary, secondary, An electrospinning method is known in which fine fibers are produced by repeating the third order.

  Such an electrospinning method uses a needle-like nozzle, so it is difficult to produce a large amount of fine fibers to be produced, and the polymer solution adheres to the tip of the nozzle, which is removed. Productivity is very poor because it is necessary to carry out regular maintenance.

  Various manufacturing methods and manufacturing apparatuses are known for improving the productivity of the electrospinning method.

JP 2007-532790 A JP 2008-127726 A JP 2012-012755 A

  The manufacturing method of the fine fiber described in patent document 1 is equipped with the spray head which has a long axis, is arrange | positioned on the surrounding wall of this spray head, has at least 1 extrusion element which has a front-end | tip part, A passage for providing the material constituting the fiber to the tip of the extrusion element is provided, and the extrusion element extends in a direction from the long axis and extracts the material from the tip of the extrusion element by an electric field. To produce fine fibers.

  As described above, according to the method for producing fine fibers described in Patent Document 1, the material constituting the fine fibers is supplied to the tip portion of the extrusion element at the peripheral wall of the spray head having the long axis, and the spray head or the collection is performed. The electric field from the long axis of the spray head to the tip of the extrusion element is used to extract and electrospin the substance from the tip of the extrusion element to form a fine fiber by rotating the body around the long axis. Can be applied to collect the fine fibers in the collecting body.

  The fine fiber manufacturing apparatus described in Patent Document 2 is rotatably supported and has a conductive cylindrical container having a plurality of small holes at a radial distance from the rotation axis, and rotationally drives the cylindrical container. Rotation drive means, high voltage generating means for charging the cylindrical container with charge, polymer solution supply means for supplying a polymer solution in which a polymer substance is dissolved in a solvent in the cylindrical container, and inside a small hole in the cylindrical container And a porous member arranged in the above, a polymer solution is supplied to the cylindrical container while rotating the cylindrical container at a predetermined speed, and a high voltage is applied to the cylindrical container. Has been.

  Thus, according to the manufacturing apparatus described in Patent Document 2, the polymer solution charged in the cylindrical container is linearly discharged from the plurality of small holes, stretched by centrifugal force, and then stretched. At the same time, as the solvent evaporates, the diameter becomes thinner and the electric charge concentrates, and the microfibers with submicron diameters can be efficiently produced by being stretched explosively by electrostatic explosion over several orders. In addition, since the porous member is arranged inside the small hole, there is no risk that the polymer solution is appropriately held by the porous member due to capillary action and droops even if the diameter of the small hole is set large. Since the whole member is always immersed in the polymer solution in the cylindrical container, the solvent of the polymer solution evaporates and the solid polymer material adheres to the periphery of the porous member or small hole. Without fear, the entire cylindrical container Stable fine fiber quality uniform from the small holes in the long-term can be stably produced over, it can be produced stably good and the fine fibers with good productivity quality with a simple configuration.

  The apparatus for producing fine fibers described in Patent Document 3 includes a raw material tank for containing an electrospinning solution, an electrospinning solution immersion means having a scraping roller rotating in the raw material tank, and the electrospinning solution attached thereto. A roller-type electrospinning apparatus comprising a chain-type application electrode that contacts the lifting roller, a collection electrode, and a high-voltage generating means connected to the chain-type application electrode and the collection electrode is described. ing.

  Thus, in the apparatus for producing fine fibers described in Patent Document 3, the chain-shaped application electrode includes beads having a three-dimensional structure of protrusions, and the electrospinning solution is easily applied to the electric field by the protrusions of the beads and is easily discharged. In addition to effectively reducing the threshold voltage required for the formation of fine fibers, the beads are evenly arranged within the range of the width of the chain-type application electrode. Thus, fine fibers can be stably discharged, and a large and uniform electrospinning effect can be achieved.

  However, the above-described conventional fine fiber production method or production apparatus is spun by the fine fiber production method described in Patent Document 1 because the spray head needs to rotate at a high speed of 1000 to 10,000 rpm. Fine fibers that are not collected by the collecting body of the fine fibers may wind around the spray head and adversely affect spinning, and regular maintenance is still required to prevent the extrusion element from becoming clogged with the polymer solution. Had the problem of being.

  In addition, the fine fiber manufacturing apparatus described in Patent Document 2 requires that the cylindrical container be rotated at a rotational speed (2000 to 3000 rpm) sufficient to generate centrifugal force, and the fine fiber that is not collected by the collector is a cylindrical container. There is a possibility that the spinning may be adversely affected, and if the porous member is clogged, it needs to be replaced, so that periodic maintenance is still necessary. .

  Furthermore, the fine fiber manufacturing apparatus described in Patent Document 3 spins fine fibers by attaching a polymer solution to a chain-type application electrode that is in contact with a lifting roller, but the polymer solution is attached to the chain-type application electrode. Since it is attached by contact with the scraping roller, it is difficult to uniformly attach the polymer solution to each bead, and there is a problem that uniform spinning cannot be performed as a whole.

  Furthermore, according to the conventional manufacturing method and manufacturing apparatus, since the electrode to which a high voltage is applied is exposed and configured, there is a risk of being injured by contacting the electrode during the manufacture of the fine fiber. It was.

  Therefore, the present invention has been made in view of the above problems, and can provide a method for producing fine fibers that can produce fine fibers that are uniformly uniform safely and easily, and that has improved productivity. Objective.

  The method for producing fine fibers according to the present invention includes a porous member that is continuous in the circumferential direction and has a large number of holes formed on the surface thereof, a supply unit that attaches a polymer solution to a part of the porous member, and the porous member A drive unit for moving the gas in the circumferential direction, a collection unit arranged on the outer circumferential side of the porous member, and a jet that ejects air toward the collection unit via the porous member inside the porous member An outlet and an electrode to which a voltage is applied by a high-voltage power supply are housed. The electrode and the polymer solution attached to the porous member by supplying electric charge from the jet outlet are charged, and the charging is performed. Fine fibers are produced by spraying the polymer solution directed toward the collection part.

  In the method for producing fine fibers according to the present invention, it is preferable that the porous member is formed in a cylindrical shape.

  In the method for producing fine fibers according to the present invention, it is preferable that the porous member is formed in an elliptic cylinder shape.

  Moreover, in the method for producing fine fibers according to the present invention, it is preferable that the ejection port is arranged with a plurality of ejection ports along the axial direction of the porous member.

  In the method for producing fine fibers according to the present invention, it is preferable that the electrode is formed along an outer edge portion of the jet port.

  In the method for producing fine fibers according to the present invention, it is preferable that the electrode is extended along the width direction of the opening of the jet port.

  The above summary of the invention does not enumerate all the necessary features of the present invention, and sub-combinations of these features can also be the invention.

  In the method for producing fine fibers according to the present invention, since the electrodes are housed in a porous member that is continuous in the circumferential direction, the electrodes are not accidentally touched during the production of the fine fibers. Since the polymer solution attached to the porous member is charged by supplying the charge of the air ejected from the jet outlet and sprayed toward the collecting portion to produce fine fibers, the polymer solution remains solidified in the porous member. And fine fibers that are uniform throughout can be produced.

The block diagram for demonstrating the outline | summary of the manufacturing method of the fine fiber which concerns on this embodiment. The perspective view of the porous member used for the manufacturing method of the fine fiber concerning this embodiment. (A) is a perspective view of the electrode used for the manufacturing method of the fine fiber which concerns on this embodiment, and a jet nozzle, (b) is a perspective view which shows the modification of an electrode. The perspective view which shows the modification of the porous member used for the manufacturing method of the fine fiber which concerns on this embodiment. The perspective view which shows the modified example of the electrode used for the manufacturing method of the fine fiber which concerns on this embodiment, and a jet nozzle.

  DESCRIPTION OF EMBODIMENTS Hereinafter, preferred embodiments for carrying out the present invention will be described with reference to the drawings. The following embodiments do not limit the invention according to each claim, and all combinations of features described in the embodiments are not necessarily essential to the solution means of the invention. .

  FIG. 1 is a configuration diagram for explaining an outline of a method for producing fine fibers according to the present embodiment, and FIG. 2 is a perspective view of a porous member used in the method for producing fine fibers according to the present embodiment. FIG. 3A is a perspective view of an electrode and an ejection port used in the method for producing fine fibers according to the present embodiment, and FIG. 3B is a perspective view showing a modification of the electrode. 4 is a perspective view showing a modified example of the porous member used in the method for producing fine fibers according to the present embodiment, and FIG. 5 shows the electrodes and jet nozzles used in the method for producing fine fibers according to the present embodiment. It is a perspective view which shows a modification.

  As shown in FIG. 1, a fine fiber production apparatus 1 used in the fine fiber production method according to the present embodiment includes a porous member 2 formed in a substantially hollow cylindrical shape continuously in the circumferential direction, and a polymer material. A supply unit 3 in which a polymer solution P in which a solution is dissolved is placed; a jet port 5 and an electrode 7 housed inside the porous member 2; a high-voltage power source 6 that applies a voltage to the electrode 7; And a collecting unit 4 to be used.

  As shown in FIG. 2, the porous member 2 is a member that is formed in a substantially cylindrical shape by continuously forming a net-like sheet having a large number of holes formed on its surface in the circumferential direction, and can be rotated in the circumferential direction by a driving unit (not shown). Is retained. The drive unit may have any configuration as long as the cylindrical porous member 2 can be driven to rotate in the circumferential direction. For example, the drive unit is preferably configured by attaching the rotary shaft of the rotary motor to the shaft end of the porous member 2. is there. The rotating shaft may be directly connected to the porous member 2 or may be connected via a speed change mechanism.

  As shown in FIG. 1, the porous member 2 is arranged so that the lower part is immersed in the polymer solution P so that the polymer solution P can be attached to the surface. Moreover, since the slit 8 extends toward the surface of the porous member 2 in the supply unit 3, the excess polymer solution P adhering to the surface of the porous member 2 is scraped off by the slit 8 to the porous member 2. The amount of the polymer solution P that adheres can be kept constant.

  Further, as shown in FIG. 3A, the jet nozzle 5 includes a supply pipe 5 b that supplies compressed air from the outside, a jet section 5 a that is continuous with the supply pipe 5 b and jets air upward toward the porous member 2. It has. An annular electrode 7 is disposed in the vicinity of the outer edge of the ejection portion 5a.

  By disposing the electrode 7 in this manner, the polymer solution P attached to the porous member 2 can be charged by supplying electric charges of air ejected from the electrode 7 and the ejection portion 5a.

  In addition, as shown in FIG.3 (b), an electrode can also be used as the acicular electrode 7 'extended along the width direction of the opening of the ejection part 5a. The needle-like electrode 7 ′ may be arranged so that the substantially central part of the opening of the ejection part 5 a coincides with the tip of the needle-like electrode 7 ′, or may be arranged so as to cross the opening. Absent.

  Further, as shown in FIG. 1, since the porous member 2 rotates in the circumferential direction, the polymer solution P adhered below the porous member 2 is moved upward along the rotation direction, and is uniformly formed by the slits 8. The air jetted from the jetting part 5 a to the polymer solution P adhering to is jetted toward the collecting part 4.

  In addition, it is suitable if the air to be ejected is ejected at 20 to 60 m / s at the outlet flow velocity at the opening of the ejection portion 5a. Moreover, since the polymer member P adhering to the surface cannot be appropriately electrospun when the porous member 2 is rotated at a high speed, the porous member 2 is preferably rotated at a speed of 3 to 20 rpm.

  In this way, since air for supplying electric charge to the polymer solution P is ejected, the distance between the charged charges of the polymer solution P becomes smaller and the acting Coulomb force becomes larger, and this Coulomb force is larger than the surface tension of the polymer solution P. The fine fiber can be produced by stretching the polymer solution P at the time of winning.

  As described above, according to the method for producing fine fibers according to the present embodiment, the polymer solution P uniformly attached to the surface of the porous member 2 is supplied with electric charges by the air ejected from the ejection port 5. Since the solution P does not adhere and the porous member 2 rotates so that the lower part is immersed in the polymer solution P, the polymer solution that has not been electrospun is immersed again in the supply unit 3, so that the solvent It is possible to prevent the polymer solution P from solidifying. In addition, since the rotational speed of the porous member 2 is low, the fine fibers F that are not collected in the collecting unit 4 do not wrap around the porous member 2, and the productivity can be improved without performing regular maintenance. An excellent method for producing fine fibers can be realized.

  Moreover, since the electrode 7 to which a high voltage is applied is housed inside the porous member 2, it is possible to prevent injuries caused by accidentally touching the electrode 7 during the production of the fine fiber. Since the rotational speed can also be set to a low speed, a safer method for producing fine fibers can be realized with a simple configuration.

  Furthermore, since the excess polymer solution P adhering to the surface of the porous member 2 is scraped off by the slits 8 and fine fibers are produced by blowing air into the polymer solution P, a uniform fine Fiber can be produced.

  In the fine fiber manufacturing method according to the present embodiment described above, the case where the shape of the porous member 2 is formed in a substantially cylindrical shape has been described. However, the shape of the porous member is not limited to this, for example, as shown in FIG. Thus, it may be formed in an elliptical cylindrical shape.

  In this case, the elliptical cylindrical porous member 2a moves in the circumferential direction like an endless track by two drive wheels, so that a plurality of jet outlets can be arranged along the long side portion. In particular, the polymer solution P attached to the surface of the porous member 2a can be electrospun.

  Moreover, in the manufacturing method of the fine fiber which concerns on this embodiment, although the jet nozzle 5 demonstrated the case where it had the single jet part 5a, as shown in FIG. 5, it is plural along the axial direction of a porous member. You may use the jet nozzle 5 'which has arrange | positioned this jet part 5'a. Furthermore, the electrodes 7 and 7 ′ are not limited to an annular shape and a needle shape, and the electrode 7 a may be formed linearly so as to cross the opening of the ejection portion 5 ′ as shown in FIG. 5. It is apparent from the scope of the claims that the embodiments added with such changes or improvements can be included in the technical scope of the present invention.

  DESCRIPTION OF SYMBOLS 1 Fine fiber manufacturing apparatus, 2 Porous member, 3 Supply part, 4 Collection part, 5, 5 'spout, 6 High voltage power supply, 7, 7a electrode, 8 slit, F fine fiber, P polymer solution.

Claims (6)

A porous member that is continuous in the circumferential direction and has a large number of holes formed on the surface;
A supply section for attaching a polymer solution to a part of the porous member;
A drive unit for moving the porous member in the circumferential direction;
A collecting portion disposed on the outer peripheral side of the porous member;
Inside the porous member, an ejection port for ejecting air toward the collection part through the porous member, and an electrode to which a voltage is applied by a high voltage power supply are housed,
The polymer solution attached to the porous member is charged by supplying electric charge from the electrode and air ejected from the ejection port, and the charged polymer solution is ejected toward the collecting portion to thereby fine fibers. A process for producing fine fibers, characterized in that In the manufacturing method of the fine fiber of Claim 1,
The method for producing fine fibers, wherein the porous member is formed in a cylindrical shape. In the manufacturing method of the fine fiber of Claim 1,
The method for producing fine fibers, wherein the porous member is formed in an elliptic cylinder shape. In the manufacturing method of the fine fiber of any one of Claim 1 to 3,
The said spout is a manufacturing method of the fine fiber characterized by the some spout being arranged along the axial direction of the said porous member. In the manufacturing method of the fine fiber of any one of Claim 1 to 4,
The said electrode is formed along the outer edge part of the said jet nozzle, The manufacturing method of the fine fiber characterized by the above-mentioned. In the manufacturing method of the fine fiber of any one of Claim 1 to 4,
The said electrode is extended along the width direction of opening of the said jet nozzle, The manufacturing method of the fine fiber characterized by the above-mentioned.

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